Etymology

Specific epithet

sinuata - sinuate, having a wavy or sinuous margin; with alternate rounded notches and lobes.

from nominative feminine singular of Latin sinuatus, participle of sinuo, "to bend or bow out in curves"

Author

N.E. Br. - Nicholas Edward Brown

Published: 1885 in Gardeners' Chronicle vol. 24

Synonyms

Alocasia bullata: bullata - bullate

More Description

(2020) Jardinerong Sunog Blogs (3)

A popular subject in horticulture, Alocasia sinuata is a small-growing Philippine endemic with bullate, thickly coriaceous, shiny leaves. The plants start out green then mature into a deeper green with almost metallic gray patina and with dark green sunken veins, resulting in a memorable foliage display of pure bliss. The species was described by Nicholas Edward Brown in 1885 from a cultivated specimen from Kew which was given by William Bull. The original collector of this plant is unknown. In the type sheet, Brown noted that it was collected in the 'Malay Archipelago' which Brown himself corrected to 'Philippines'. A photo of the holotype can be viewed here. (Fig. 2)

What is notable in the type specimen is the very deep sinus with rather distant posterior lobes. However, as noted by George Yao, an ardent student of Araceae in the Philippines, posterior lobing and sinus depth is variable in Alocasia anyway. Alocasia sinuata was so-named for the sinuate (wavy) margins, but as the holotype and many cultivated plants show, the waviness of the blade margins are poorly expressed. Below is a photo of a Ramos & Pascasio collection from Surigao. Note how one leaf is decidedly peltate: click here (Fig. 3)

The photos presented here were taken from Samar, and the plants grow in shade with their roots attached directly on limestone facing an estuary at an elevation of about 10 m asl. Leaf litter and thin mats of mosses partially cover the base of the plants including the petioles. The roots are kept moist by the drippings (Samar is known for its extensive cave systems and this habitat is one of those) but the almost fully vertical manner in which these plants grow ensures that waterlogging is never an issue. Air circulation is constant which brings cooling breeze 24/7.

To give you an idea of the prevailing conditions, here is a photo of a tree limb occupied by epiphytes and mosses. (Fig. 4)

A young plant of A. sinuata with typical green leaf coloration. (Fig. 5)

Subadult specimen with leaves already tending toward gray-green. (Fig. 6)

Mature plants rooting on extensive forest debris. This photo is manipulated to better show the plants; this spot, in reality, is much shadier than illustrated here. (Fig. 7)

Most of the plants shown in this rather bad photo have non-peltate leaves. (Fig. 8)

Alocasia sinuata is also known from Palawan, Leyte, and Mindanao. However, the Palawan specimen (cultivated at The Missouri Botanical Garden and originally collected by Tom Croat) has a suite of characters said to not fully fit the species, such as in the much attenuated sterile interstice and secondary venation not forming subsidiary veins, though otherwise matching A. sinuata (Hay 1999). Finding these plants in Palawan and studying the population as a whole is needed to elucidate their exact identity. Some plants in cultivation, I should add, appear to have watered-down A. sinuata traits and may be hybrids.

(1885) The Gardeners' Chronicle vol. 24 p. 678 (4)

See (Fig. 9), as noted in the holotype herbarium specimen of A. sinuata (Fig. 2); scroll down for the holotype specimen's link.

ALOCASIA SINUATA, N. E. Br., n. sp.

This is a very striking and distinct novelty, recently introduced by Mr. W. Bull from the Malay Archipelago. It is a handsome plant, very different from anything else at present in cultivation, so far as known to me, and remarkable for the unusual number of leaves produced by each crown, which, taken in conjunction with their fine dark colour and the strongly sinuate margin of the blade, make it a very ornamental and highly effective foliage plant, and one of the most striking Aroids that I have seen for some time. The specimen from which the description given below was made, was a flowering plant, and I am informed by Mr. Bull was very much below the average size, and that according to the statements of the collector a full grown plant would be about 4 or 5 feet in diameter; a grand and noble Aroid. From this it will be understood that the dimensions given below are introduced to show the proportions of the various parts. The boat-shaped limb of the bracts is a remarkable character, and well illustrates the transition from the blade of a leaf to a spathe, and indeed it is very similar to the limb of the actual spathe. I have not noticed it in any other species. This plant is also interesting as forming a connecting link between Alocasia and Schizocasia, and I am now, after examining this species inclined to adopt Engler's former view, that the two genera should be united.

Leaves numerous (for an Alocasia). Petiole 6 inches long, flattened on the face, rounded on the back, sheathing at the base, dull green. Lamina sagittate, with strongly marked sinuous margins, 9 inches long, 4 inches broad (growing to a very much larger size), the front lobe oblong, very obtuse, with a short triangular point, the basal lobes about half as long as the front lobe, triangular, obtuse, with straight inner margins, and separated by an acute triangular sinus. Primary lateral veins about seven or eight on each side of the midrib, spreading, straight or variously curved, the four lower ones stout and rather distant ; those near the apex much more slender and closer together. The postical branches of the midrib which run into the posterior lobes, give off two distant lateral veins from their upper edge; intramarginal vein about 3/4-line distant from the margin. All the veins are strongly impressed above and prominent beneath, making the surface somewhat bullate. The upper surface of young leaves is of a very dark green along the principal veins, and of a lighter cheerful green between them ; but in old leaves the lighter green deepens and becomes less distinguishable, although the contrast is still evident. Under surface whitish-green, with the principal veins darker. Scapes several, from the centre of the rosette of leaves, each with two sheathing bracts, the outer furnished with a stalked, lanceolate, acute, boat-shaped, green lamina ; the inner membranous, lanceolate, acute, concealed within the sheath of the outer bract. Scape 8 inches long, 1/4 inch thick, slightly compressed, terete, light green. Spathe about 3 inches long (tube 7 - 8 lines long, lamina 2 1/2 inches long), entirely light green inside and out; tube a little compressed, ellipsoidal, nearly as broad as long, lamina erect, narrow boat-shaped, about 1/2 inch broad, convolute-acuminate at apex. Spadix 2 1/4 - 2 1/2 inches long (female part 4 lines, neuter part between ovaries and stamens 5 lines, male part 1/2 inch, and the cylindric-conoidal appendix 1 - 1 1/4 inch long), ovaries rather few, in two or three whorls, globose, green, with a large 3 – 4 lobed whitish stigma; the rest of the spadix milk-white. Malay Archipelago.

N. E. Brown, Herbarium, Kew.